1. Field of the Invention
The present invention relates to a disk player, and a turntable, a clamper and a spindle motor which are adopted for the same and, more particularly, to a disk player having a self-compensating dynamic balancer for restricting internal vibrations generated due to an eccentric center of gravity of a disk, and a turntable incorporating the self-compensating dynamic balancer, a clamper incorporating the self-compensating dynamic balancer and a spindle motor incorporating the self-compensating dynamic balancer which are adopted for the same.
2. Description of the Related Art
In general, a disk player records and/or reads information onto and/or from a recording medium such as a compact disk (CD), a CD-ROM and a digital versatile disk (DVD). Due to its sensitivity, the disk player is required to protect the disk and optical pickup from external impacts and internal vibrations.
A typical disk player, as shown in FIG. 1, includes a deck base 10 hinge-coupled to a housing (not shown) to be capable of rotating vertically, a deck plate 20 coupled to the deck base 10, a spindle motor 21 installed at the deck plate 20 for providing a rotational force to a disk 1, a turntable 23 coupled to a rotational shaft 22 of the spindle motor 21 for accommodating the disk 1, a damper 40 installed on the inner surface of the upper portion of the housing to face the turntable 23 for securing the disk 1 placed on the turntable 23, and an optical pickup 25 coupled to the deck plate 20 to be capable of moving across the disk 1 for performing recording and reproduction operations. The disk player includes buffering members 30 disposed between the deck base 10 and the deck plate 20 to prevent the external vibrations transferred through the deck base 10 from being transferred directly to the deck plate 20, the spindle motor 21 and the optical pickup 25. The buffering members 30 are formed of a material such as soft rubber or polyurethane which can absorb external impacts.
The disk player adopting the buffering members 30 as above can effectively protect the driving of the disk 1 and the optical pickup 25 from external impacts. However, a method of dampening internal vibrations generated by the rotation of the spindle motor 21 due to an eccentric center of gravity of the disk is not taken into consideration. In such a case, the eccentric center of gravity of the disk is caused by a discrepancy between the rotational center of the disk and the center of gravity of the disk due to errors in the manufacturing process of the disk. Thus, the rotational shaft of the spindle motor 21 s exhibits an orbital revolution due to wobbling of the rotational shaft.
Such orbital revolution of the rotational shaft of the spindle motor does not effect a low-speed disk player such as a 1X or 2X type. However, in the case of a high-speed model such as a 6X, 8X, 12X, 20X or 24X type, the effects of the orbital revolution of the rotational shaft of the spindle motor become serious making the recording/reproducing of information difficult.
To overcome the above problems, in a conventional high-speed disk player, the mass of the deck plate where the spindle motor is installed is increased or the rigidity of the buffering members is increased to reduce movements of the deck plate due to the eccentric center of gravity of the disk.
However, not only is the deck plate having increased mass inappropriate for a high speed rotation, but also the costs of the product increase and miniaturization of the product is hindered. Also, when the rigidity of the buffering members is increased, it is not possible to effectively dampen the external impacts or vibrations.
To solve the above problems, it is a first objective of the present invention to provide a disk player in which external vibrations can be reduced and also internal vibrations generated due to an eccentric center of gravity of a disk can be limited without an increase in weight.
It is a second objective of the present invention to provide a turntable incorporating a self-compensating dynamic balancer, which is employed in a disk player so that the internal vibrations due to an eccentric center of gravity of a disk can be limited.
It is a third objective of the present invention to provide a damper incorporating a self-compensating dynamic balancer, which is employed in a disk player so that the internal vibrations due to an eccentric center of gravity of a disk can be limited.
It is a fourth objective of the present invention to provide a spindle motor incorporating a self-compensating dynamic balancer, which is employed in a disk player so that the internal vibrations due to an eccentric center of gravity of a disk can be limited.
Accordingly, to achieve the first objective, there is provided a disk player comprising a deck base, a deck plate elastically coupled to the deck base, at least one buffering member interposed between the deck base and the deck plate for protecting the deck plate from external impacts, a spindle motor having a rotational shaft and being mounted to the deck plate for providing a rotational force to a disk, a turntable mounted to the rotational shaft of the spindle motor for accommodating the disk, a clamper for holding the disk in place on the turntable, an optical pickup installed at the deck plate to be capable of moving across the disk, and a self-compensating dynamic balancer mounted to at least one among members which are rotated by the rotational force provided by the spindle motor, the center of gravity of the self-compensating dynamic balancer being located opposite to that of the disk with respect to the rotational shaft of the spindle motor by a centrifugal force generated during rotation of the disk.
To achieve the second objective, there is provided a turntable incorporating a self-compensating dynamic balancer adopted in a disk player comprising a placing member having a coupling hole which is coupled to a rotational shaft of a motor and a surface on which a disk is placed, the placing member being rotated by rotation of the motor, a coupling protrusion which is formed on the placing member to project therefrom and into which the center hole of a disk fits, at least one circular race which is formed in the placing member and rotates around the rotation center of the placing member, a mobile unit which is placed inside the race to be capable of moving, a cover member to cover an opening of the race.
To achieve the third objective, there is provided a damper incorporating a self-compensating dynamic balancer adopted in a disk player comprising a clamper main body, a pressing unit which is installed at the clamper main body for pressing a disk placed on a turntable, at least one circular race which is formed in the clamper main body and rotates around the center of rotation of the damper main body, a mobile unit placed inside the race to be capable of moving, and a cover member which covers an opening of the race.
To achieve the fourth objective, there is provided a spindle motor incorporating a self-compensating dynamic balancer adopted in disk player comprising a rotational shaft, a motor base having a through hole in which the rotational shaft is rotatably inserted, a stator fixedly installed at the motor base and having a yoke and a coil wound around the yoke, a rotor having a case which is fixed to an end of the rotational shaft and encloses the stator, and a magnet which is fixed inside the case to face the yoke, at least one circular race which is integrally formed with the case and rotates around the center of rotation of the rotational shaft, a mobile unit located inside the race to be capable of moving, and a cover member which is coupled to an opening of the race for sealing the inner space of the race.